Pump wear plate



Aug. 28, 1962 R. o. BAYER ETAL PUMP WEAR PLATE Filed April 21, 1960 United States Patent M 3,050,846 PUMP WEAR PLATE Robert 0. Bayer, Wilmington, DeL, and Roy C. Meinzer,

Kennett Square, Pa., assignors to E. I. du Pont de lflernours and Company, Wilmington, DeL, a corporation of Delaware Filed Apr. 21, 1960, Ser. No. 23,842 4 Claims. (Cl. 29-527) This invention relates generally to the production of castings and, more particularly, to those castings which include one or more tortuous flow passages.

One accepted procedure for fabricating parts provided with such passages has been disclosed by Corvin in US. Patent No. 1,234,878 and involves the steps of bending a conduit-forming tube to the desired configuration, supporting the bent tube in a mold cavity, and casting about the tube. Although the tube is used in the same manner as a core, it becomes a permanent and integral part of the casting and forms an accurate, smooth-walled conduit following either a regular or an irregular path. In many instances, this procedure is preferred to those in which tortuous passages are formed by drilling intersecting holes and plugging certain of the holes or by casting about a destructible core. None of these procedures ofiers the degree of precision which is required when the location of entry and exit ports in a finished casting such as a pump mounting plate is critical.

The most important object of the present invention is to provide for the precise location of entry and exit ports in a casting otherwise produced in the manner taught by Corvin.

It is a further object of the invention to improve on, known procedures by the incorporation of method steps which facilitate the location of such ports within very close tolerances.

With these and other objects in view, the fabrication procedures disclosed herein involve the initial steps of bending a tube to the desired configuration, casting about the tube, and machining each end of the tube flush with a surface of the casting. The precise location of the tube orifices is accomplished by ramming each end of the tube to present an upset portion beneath the surface of the casting, machining the casting and the tube to a new surface intersecting the upset portion, and drilling through the upset portion to provide an orifice of the desired size at the desired location on the new surface.

Additional objectives will become apparent in the following specification wherein reference is made by the use of designating numerals to the accompanying drawing in which:

FIGURES l6 illustrate successive stages in the fabri cation of a casting according to the teachings of the present invention; and

FIGS. 7 and 8 are top and side views, respectively, of a finished casting.

After the design of a particular casting has been worked out, the first step in its fabrication is that of bending one or more tubes 10 to the configuration of the tortuous passages which will pass through the finished casting. Such a tube, which is shown fiagmentarily in FIG. 1, is usually of seamless steel. The metal chosen for the tube must have a higher fusibility than the casting material. The formation of branched passages by Welding or otherwise joining a pair of bent tubes is also contemplated.

When the necessary tubes have been prepared, their ends are supported in fixtures 12 (FIG. 2) within a conventional mold cavity as a casting 14 is poured. After removal from the mold and the fixtures 12, tubes 10 are embedded in and project at each end thereof from casting 14, as shown at 16 in FIG. 3. The next step in- $650,846 Patented Aug. 28, 1962 volves machining the end 16 until the tube is flush with a surface 18 of the casting.

As noted previously, the present invention is directed primarily to the manner in which the as-cast orifices of the tubes 10 are relocated within precise tolerances. This is accomplished by ramming (FIG. 4) or otherwise upsetting each tube end to produce an upset portion 20 beneath the surface 18. The inside diameter of the tube 10 is preferably reduced during the ramming step to a point where the through passage is nearly closed. -A ramis shown fragmentarily in FIG. 4 and designated with the numeral 22. Both the casting l4 and the tube 10 are then machined, by turn'mg, milling or a similar operation, to present a new surface 18' (FIG. 5) which intersects the upset portion 20. In the final step, the remainder of the upset portion is drilled according to the design specification so as to provide a precisely located orifice 24, as shown in FIG. 6. With available equipment, each orifice may be located within tolerances of $0.001 inch, or better.

The method improvements of the present invention have been described above in their preferred embodiment. In some circumstances, it may be desirable to vary the order in which the steps are accomplished. For example, the tube ends could be upset before the bending and/ or casting steps. This latter procedure has proved more difficult in view of the difiiculties involved in upsetting and in supporting the bent and upset tubes in a mold.

The improvement steps disclosed herein have particular utility in the fabrication of parts such as the pump adaptor plate illustrated in FIGS. 7 and 8. A gear pump (not shown )is fastened to a plate 30 by fasteners which pass through apertures 32. The latter have been omitted from FIG. 8 for purposes of clarity. Plate 30 is provided with a gasket-receiving ledge 36 surrounding a fluid entry port 34. Port 34 communicates through branched passages 38, 40 with pump ports 42, 44. The fluid is' discharged from the pump to ports 46, 48 and exits through ports 50, 52. In addition to the pump, the associated feed and delivery pipes are coupled to plate 30 and communicate with ports 36, 50, 52.

It is apparent that changes and modifications may be made in the disclosed method and that the latter may be applied to the production of various useful machinery elements of the general type shown in FIGS. 7 and 8 Without departing from the spirit of the present invention which is therefore intended to be limited only by the scope of the appended claims.

We claim:

1. A method of relocating the orifice of a tube embedded in and having at least one of its ends substantially flush with a surface of an integral casting, said tube being of a material having a higher fusibility than said casting, said method comprising the steps of: upsetting said one end of the tube, thereby partially closing it and leaving an upset portion beneath said casting surface; machining the casting and the tube to a new surface intersecting the upset portion; and drilling through said portion to provide an orifice therein of the desired size at the desired location on said new surface.

2. A method of relocating the orifice of a tube embedded in and having at least one of its ends substantially flush with a surface of an integral casting, said tube being of a material having a higher fusibility than said casting, said method comprising the steps of: ramming said one end of the tube, thereby partially closing it and leaving an upset portion beneath said casting surface; machining the casting and the tube to a new surface intersecting the upset portion; and drilling through said porton to proved an orifice therein of the desired size at the desired location on said new surface.

3. In the fabrication of a pump adaptor plate having flow passages, the steps of: bending a flow tube to the desired configuration of a passage; supporting the ends of said tube in a mold; casting a plate integral with and about the tube, said tube'being of a material having a higher fusibilitv than said casting; machining theplate and/ortube until the tube ends are substantially flush with corresponding surfaces of the plate; upsettingeach end' of the tube, leaving an enlargement beneath the surface of the plate and a reduced passage through the tubeg'machining the plate and tube to present a new sur-' face intersecting each reduced passage; and drilling through each enlargement to provide an orifice therein of the desired size at'the desired location on'said new surface. e i i 4. A method of providing a tortuous passage in a finished casting which method includes the steps of bending a tube to the desired configuration of the passage,

' 7 4 supporting the ends of said the bent tube, said. tube being of a material having a higher fusibility than the casting; and machining each end of the tube flush with a surface of the casting, the V improvement of which comprises: ramming each end of the tube, leaving an upset portion beneath the'corre sponding surface of't he casting; machining the casting and tube to a new surface intersecting each portion; and drill ing through each portion to provide an orifice therein of j the desired size at the desired location on said new surface.

References Cited in the file of this patent UNITED STATES PATENTS tube a mold, casting about Carlson Aug 31,1226 

